The invention of the present application relates to antibacterial agents for drug-resistant bacteria and anti-Chlamydia agents. More particularly, the present invention relates to novel antibacterial agents for drug-resistant bacteria and anti-Chlamydia agents, which comprise highly active furanonaphthoquinone derivatives as effective components.
In recent years, methicillin-resistant Staphylococcus aureus (MRSA) has been seriously considered as the causal bacterium of hospital infection. Since this MRSA is a multiple drug resistant bacterium for a variety of antibiotics, there is a limitation to the drugs that may be used effectively as therapeutic agents.
Additionally, at present, no antibacterial agent is known which show a stronger antibiotic activity against MRSA (resistant bacterium) than against MSSA (sensitive bacterium).
Accordingly, the realization of antibacterial agents for drug-resistant bacteria with high antibacterial activity has been strongly desired.
On the other hand, Chlamydia is a spherical bacterium of 0.2 xcexcm in diameter, which is known to be the causal bacterium of parrot fever infected from pet birds (accompanied with fever, headache, and pneumonia), infections caused by sexual intercourse, urethritis, cervicitis, lymphogranuloma venereum, conjunctivitis, pneumonia, etc. In Asia and Africa, trachoma accompanying blindness is raging. In addition, recent studies have found Chlamydia infections, which cause infertility in women and arteriosclerosis.
Although antibiotics such as macrolide derivatives and tetracycline derivatives have been used as therapeutic agents, in practice, the incidence rate is reported to be higher than that of gonorrhea.
Moreover, since recent new drugs have broad spectra, the acquisition of resistance of other bacteria against drugs has become a problem. Therefore, the development of novel highly specific anti-Chlamydia agents of which the action mechanism is different from that of the drugs known so far, is anticipated.
In this situation, as a means to solve the above-mentioned problem, the invention of the present application provides antibacterial agents for drug-resistant bacteria and anti-Chlamydia agents comprising, as the effective component, the furanonaphthoquinone derivative represented by the following formula (1): 
wherein each R may be the same or different representing any one of the following (a) to (e): 
(wherein Rxe2x80x2 is a hydrogen atom, alkyl group, hydroxyalkyl group, or alkoxyalkyl group), or two mutually adjacent Rs may be bonded via an oxygen atom to form a heterocyclic ring.
In the anti-viral agents and antibacterial agents of the present invention described above, wherein furanonaphthoquinone derivatives are used as the effective component, a wide variety of furanonaphthoquinone derivatives may be used. These are exemplified by, for example, 2-methylnaphtho[2,3-b]furan-4,9-dione, 2-acetylnaphtho[2,3-b]furan-4,9-dione, 2-(1-hydroxyethyl)naphtho[2,3-b]furan-4,9-dione, naphtho[2,3-b]furan-4,9-dione, 5(or 8)-hydroxy-2-(1-hydroxyethyl)naphtho[2,3-b]furan-4,9-dione, 5(or 8)-hydroxynaphtho[2,3-b]furan-4,9-dione, 2-methyl-5(or 8)-hydroxy-2-methylnaphtho[2,3-b]furan-4,9-dione, 1,3-dimethylisofuranonaphthoquinone, 2-(acetylethylenacetal)naphtho[2,3-b]furan-4,9-dione, 8-hydroxy-7-methoxynaphtho-[2,3-b]furan-4,9-dione, 3-acetyl-5,8-dimethoxy-2-methylnaphtho[2,3-b]furan-4,9-dione, etc. The furanonaphthoquinone derivatives used in this invention are not limited to these examples, and a variety of embodiments represented by the above formula maybe included. In addition, to the alkyl group, hydroxyalkyl group, and alkoxyalkyl group of the above formula, other substituents such as alkenyl group, cycloalkyl group, cycloalkenyl group, aryl group, halogen atom, amino group, nitro group, cyano group, thiol group, thioether group, carboxyl group, ester group, amide group, sulfonyl group, haloformyl group, heterocyclic group, etc., may optionally be attached, as long as they do not interfere with the activity.
These various compounds may be produced by a variety of known methods of chemical synthesis or by methods such as the extraction of naphthoquinone as natural product from bark, etc.
The mode for carrying out the invention is explained in more detail by the following examples.